Symptom Checks

Check the following items:

• Check ignition system. See CIRCUIT TEST JD in TESTS W/CODES article.
• Check fuel delivery system. See CIRCUIT TEST HB (natural gas vehicles) or CIRCUIT TEST HC (except natural gas vehicles) in TESTS W/CODES article.
• Check exhaust system for restriction. See step 7) of CIRCUIT TEST HF in TESTS W/CODES article.
• Check engine compression and valve timing. Check engine mechanical condition.